The Basic Knowledge of DALI Dimming

DALI dimming is a typical digital control dimming method. The World DALI Group was established in 2001. The introduction and application of DALI technology has become the mainstream standard for digital dimming in Europe.

 

DALI – Digital Addressable Lighting Interface

  • Digital Control Topology
  • Allows for individual addressing of ballasts/drivers
  • Uses digital signals to send and receive information to ballasts/drivers through low voltage wiring
  • Developed as a ballast communication standard (IEC 60929 Annex E)
  • Now the standard exists in IEC 62386

 

DALI Control

  • DALI is an “open” protocol that sets base-level requirements for control and load interaction
  • Manufacturers add features to their “DALI-compatible” products to make them more robust and user-friendly, effectively creating proprietary DALI systems
  • Mixing DALI controls with DALI ballasts/drivers from different manufacturers can result in incompatibility and poor performance

 

DALI Control IEC 60929

  • Accepted as an international standard in 2002
  • Developed as an upgrade/alternative to 0-10 Volt control
  • DALI group continues to improve and expand the standard
  • Does not define dimming quality or dimming performance

 

DALI: What’s in the standard?

In the ratified DALI protocol Up to the manufacturer(s)
Communicate to all fixtures at once with a single command (broadcast) X
Communicate to up to 16 unique groups of fixtures with a single command X
Communicate to more than 16 unique groups of fixtures with a single command X
Communicate to a single fixture X
Ask a fixture what level it is at X
Ask a fixture if there is a lamp or ballast failure X
Report energy data for a single fixture X
Automatically replace a failed ballast X
Determine priority of daylight sensor, occupancy sensor, personal control, timeclock, etc. X
Tested compatibility of controls, ballasts, and drivers X

 

What it CAN do:

  • Up to 64 digitally addressable lighting fixtures
  • Individually controlled or as part of a group/scene
  • Can be easily re-zoned or re-grouped
  • Simplify installation (easier to retrofit than 0-10V)
  • Ballasts take standard power wiring
  • Power and control wiring are independent
  • Communication wiring between ballasts and the master control is polarity & topology free

 

What it CAN NOT do:

  • Communication beyond a master control querying the ballasts
  • All communication must go through the master control (changing in the DALI controls protocol)
  • The last DALI command wins
  • If a manual control says to be off, a daylight sensor can override and turn the lights on
  • Procedures & requirements for backing up system programming are not defined
  • Results in systems needing re-commissioning when a ballast fails
  • System startup and programming (commissioning) required

 

Summary

  • DALI protocol defines the basic operation of a system
  • Manufacturers often go above and beyond the standard to gain a competitive advantage
  • This results in DALI controls from one manufacturer not being compatible with DALI controls from another
  • There isn’t 3rd party verification

Post time: Jul-12-2019
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